The medical optics art has suggested several instruments for ophthalmic surgery, and particularly noninvasive surgery using a YAG laser (Pulsed Neodymium: Yitrium-Aluminum-Garnet). The surgical YAG laser beam is first expanded and then converged on the eye so that when the beam concentrates at a focal point within the eye it vaporizes tissue at that point. A succession of carefully positioned laser pulses can destroy tissue within the eye and accomplish some surgical procedures noninvasively.
For aiming and delivering a surgical laser pulse precisely, instruments use a binocular microscope and visible beams from a laser such as a Helium-Neon (He-Ne) laser converging on a focal point coincident with the focal point of the surgical laser beam. While viewing the eye through the microscope, the surgeon can fix the exact location of the focal point for the visible beams and can then deliver a surgically effective pulse at the predetermined point. It is important to locate the focal point of the surgical laser beam accurately in three dimensions to within fractions of a millimeter, and this requires an optical system that can make the focal point of the visible beams clearly viewable and accurately coincident with the surgical laser beam.
I have devised an optical system for a surgical ophthalmic laser instrument that uses light more efficiently, allowing the optical system to be more compact and more accurately combined with the microscope. My system also accurately holds a precise adjustment in the coincidence of the focal points of visible and surgical beams. It results in a compact, sturdy, accurate, and reliable instrument that reduces the chances for error to help and protect both the surgeon and the patient.